Smear Layer Evaluation on Root Canal Preparation with...

Smear Layer Evaluation on Root Canal Preparation….Manjunatha M et al

ORIGINAL RESEARCH

Journal of International Oral Health. Jan-Feb 2013; 5(1):66-78 [ 66 ]

Smear Layer Evaluation on Root Canal Preparation with Manual and

Rotary Techniques using EDTA as an Irrigant: A Scanning Electron

Microscopy Study. Manjunatha M1, Annapurna Kini2, Sudhakar V3, Sunil Kumar VC4, Vinay Kumar Hiremath5, Ankur Shah6 1Reader, Bhabha College of Dental Sciences, Bhopal, Madhya Pradesh, India; 2Reader, Rajarajeshwari Dental College, Bangalore, India;

3Reader, Mansarovar Dental college and Hospital, Bhopal, Madhya Pradesh, India; 4Reader, Bhabha College of Dental Sciences, Bhopal,

Madhya Pradesh, India; 5Principal, Professor and HOD, Mansarovar Dental College and Hospital, Bhopal, Madhya Pradesh, India; 6Senior

Lecturer, Aditya Dental College, Beed, Maharastra, India.

ABSTRACT

Introduction: The aim of any root canal treatment is to achieve a canal free of micro organisms, residual pulp

remnants, debris and smear layer for the long term success of the procedure. Manual and automated

instrumentation techniques along with proper irrigation regime is used to arrive at the aforementioned goal. Many

authors focused on the preparation capabilities of various manual and rotary instruments but very few

investigators stressed on the actual cleaning abilities of these instruments.

Aims and objectives: This study was undertaken to evaluate the cleaning efficiency of manual K flex files and

rotary Pro File systems in the root canals using a scanning electron microscope.

Material and Methods: Thirty single rooted mandibular first premolars were divided into two groups and

randomized (the manual group-M and the ProFile group-P) with respect to the preparation technique. The Manual

group was hand instrumented with stainless steel K- Flexofiles by means of a conventional filing technique. The

Pro File group was instrumented according to the manufacturer’s instructions using a rotary handpiece. All canals

were shaped and cleaned under frequent irrigation with EDTA. Final irrigation was carried out with 3 mL of

normal saline solution to neutralize the action of the irrigant. The roots were split, one half of each tooth was

selected for further SEM technique analysis and examined under the scanning electron microscope. The canal walls

were quantitatively evaluated for the amount of debris and smear layer. The apical, middle and coronal regions of

the canal surface, were graded (1-5) for debris and smear layer. A statistical analysis was performed using a Mann-

Whitney Rank Sum test. ProFile performed least effective cleaning. Manual K-Flexofiles led to a grooved pattern.

Results and Conclusion: A statistically significant difference was observed (p<0.05) between the two

instrumentation techniques concerning the amount of debris and smear layer at the apical level. The manually filed

canals had less debris and smear layer than those using a rotary technique. It was concluded from this study that

none of the instrumentation techniques employed, produced the canal walls which were free of surface debris and

smear layer. The manual instrumentation technique was better in cleaning the canals compared to the ProFile

rotary Ni-Ti instruments despite the step-back technique used for manual instrumentation.

Key words: Clinical research, Tooth loss, Oral Health.

How to cite this article: Manjunatha M, Kini A, Sudhakar V, Sunil K V C, Hiremath V K, Shah A. Smear Layer

Evaluation on Root Canal Preparation with Manual and Rotary Techniques using EDTA as an Irrigant: A Scanning

Electron Microscopy Study. J Int Oral Health 2013; 5(1):66-78.

Source of Support: Nil Conflict of Interest: None Declared

Received: 10th November 2012 Reviewed: 6th December 2013 Accepted: 12th January 2013

Address for Correspondence: Dr Sudhakar V, Mansarovar Dental college and Hospital, Bhopal, Madhya Pradesh,

India, Mobile: (+91) 9880000666, e-mail: [email protected].


ORIGINAL RESEARCH


Photograph 1: Photomicrograph Showing Debris-

Score 1.


Score 2


Score 3.


Score 4

Introduction

The main objectives of cleaning and shaping of

root canal is to eliminate residual pulp tissue,

removal of debris and the maintenance of the

original canal curvature. Based on the evidence of

several studies on the instrumented canals, it was

found that it is difficult to completely clean the

root canals, especially the curved ones.1, 2, 3, 4

Removal of smear layer prior to root canal

obturation remains controversial. It has been

suggested that the smear layer may decrease the

permeability of dentin and prevent bacterial

penetration into underlying dentinal tubules.5

Most of the authors believe that the smear layer

may prevent antimicrobial agents from gaining

access to underlying contaminated dentinal

tubules.6, 7

Several studies have indicated that cleaning

ability of manual root-canal instrumentation is

found to be superior to automated devices.3,8,9

However, certain studies have shown superiority

of automated devices using rotary nickel-titanium

instruments with various tapers, even in severely

curved root canals.

Since most of the studies conducted focused little

on the cleaning ability of the rotary Ni-Ti

instruments, this study was undertaken for a

comparative evaluation of the cleaning ability of

rotary Ni-Ti instrumentation technique and

manual instrumentation technique using scanning

electron microscope.

Aims and Objectives:

Compare the cleanliness of the root canal walls

either with the manual technique and rotary

technique of canal instrumentation.


ORIGINAL RESEARCH



Score 5

Photograph 6: Photomicrograph Showing Smear

Layer - Score 1


Layer - Score 2


Layer - Score 3

Check the amount of debris and smear layer

present on the canal walls at the cervical, middle

and apical thirds after hand instrumentation or a

rotary technique of instrumentation.

Materials and Methods:

Thirty single rooted mandibular first premolars

which were extracted for orthodontic reasons

were selected. Following extraction, the teeth

were rinsed in tap water in order to remove blood

and tissue debris, stored in 0.2% Chlorhexidine

Gluconate till usage. Access cavities were

prepared according to the standard extension for

optimal inspection of root canal openings.

The teeth were divided into two groups and

randomized (the manual group-M and the ProFile

group-P) with respect to the preparation

technique. The Manual group was hand

instrumented with stainless steel K- Flexofiles by

means of a conventional filing technique, i.e. the

canal was enlarged along its entire length. The

instruments were inserted to the working length

(WL), twisted or bound and withdrawn by forcing

them against the walls. Working length was

determined with a size 10 K- File, which was

inserted until it reached the apical foramen and

one-half millimeter subtracted from this length.

Filing motions were repeated until that particular

size file was loose.10 This was repeated

successively with larger instruments of sizes 15-

35.

The ProFile group was instrumented with rotary

Ni-Ti files in a 250- r.p.m. handpiece to size 35

(.06). The instruments were used in the canal with

a continuous, slight in and out passive movement


ORIGINAL RESEARCH



Layer - Score 4 Photograph 10: Photomicrograph Showing Smear

Layer - Score 5

Graph 1: Mean Cervical Debris Score among the

Study Group Graph 2: Mean Cervical Smear Layer Score among

the Study Group

with intermittent irrigation with EDTA and were

never forced apically. The operation sequence

comprised four phases: 1) crown-down, 2)

determination of the working length, 3) apical

preparation and 4) final shaping.

The protocol was as follows:

For crown-down preparation the instruments

25.06 and 20.06 were introduced successively at

250 r.p.m. into the canal until resistance was

perceived by the operator or approximately half

to possibly two-thirds of the length of the

estimated canal.

Canal preparation proceeded using the 25.04 and

20.04 instruments in a similar way but not beyond

three-quarters of the estimated canal length. The

optimal depth of the root canal (Working Length)

was determined by inserting a size 10 K- File

until it reached the apical foramen and

subtracting one- half millimeter from this length.

The apical stop at the working length was created

using 15.04, 20.04, 25.04 instruments.

The final shaping achieved to working length was

performed successively by means of 20.06, 25.06,

30.06, 35.06 instruments.

All canals were shaped and cleaned under

frequent irrigation with EDTA. Final irrigation

was carried out with 3 ml of normal saline

solution to neutralize the action of the irrigant. All

canals were dried with sterile adsorbent paper

points.

The roots were split using a tapering fissure

diamond bur cutting a groove in a longitudinal

direction. To avoid contamination of the canals by

the separation process, the last part of the

separation was performed by splitting the root


ORIGINAL RESEARCH


Graph 3: Mean Middle Debris Score among the

Study Group

Graph 4 : Mean Middle Smear Layer Score among

the Study Group

Graph 5: Mean Apical Debris Score among the

Study Group

with a chisel. The root halves were cleaned from

grinding material and dried using water- and air-

blasting for three seconds. One half of each tooth

was selected for further SEM technique analysis.

The criteria for use were that the root canal wall

should be intact and available for quantitative

measurements at apical, middle and coronal level.

The specimens were left to dry overnight. The

root sections were mounted on aluminium stub,

sputter-coated with 10% gold-palladium in the

sputtering machine (JFC-1100E, Ion Sputtering

Device) and examined under the scanning

electron microscope (JEOL, JSM-840 A Scanning

Microscope, Tokyo, Japan).

The entire surface and each region (apical, middle

and coronal) of each canal were examined at a

magnifications ranging from x12 to x1500. The

micrographs depicting a magnification x200 were

chosen for the analysis.

The canal walls were quantitatively evaluated for

the amount of debris and smear layer.

Debris was defined as dentine chips, pulpal

remnants or other particles loosely stuck to the

canal wall.3

Debris were scored as follows

Score 1: clean root canal wall, very slight debris

(photograph 1)

Score 2: slight debris (photograph 2)

Score 3: moderate amount of debris, less than 50%

of the sample surface covered (photograph 3)

Score 4: substantial debris, more than 50% of the

sample surface covered (photograph 4)

Score 5: the root canal sample was completely or

almost completely covered with debris

(photograph 5)

Smear layer3 was scored as follows

Score 1: no smear layer, open dentinal tubuli

(photograph 6)


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Graph 6: Mean Apícal Smear Layer Score among

the Study Group

Table 1: Scores of Debris and Smear Layer Recorded

M- GROUP P- GROUP

Scores Cervical Middle Apical Cervical Middle Apical

Debris

1 4 - - 3 3 -

2 9 12 7 6 6 -

3 2 3 4 6 6 8

4 - - 2 - - 4

5 - - 2 - - 3

Smear layer

1 6 - - 5 2 -

2 8 9 5 10 7 -

3 1 6 5 - 6 5

4 - - 4 - - 7

5 - - 1 - - 3

n=15

Score 2: slight smear layer, most tubuli were

open (photograph 7)

Score 3: homogeneous smear layer covering the

major part of the surface, a few dentinal tubuli

open (photograph 8)

Score 4: homogeneous smear layer covering the

surface, no dentinal tubuli open (photograph 9)

Score 5: thick non-homogeneous smear layer

covering the surface (photograph 10)

Central beam of SEM was directed to the centre of

the object by the SEM- operator under x12

magnification and the magnification was

increased gradually to x1500. The canal wall

region appearing on the screen at x200

magnification was scored. The scoring was done

by a second operator who could not identify the

coded specimens nor the device used for root

canal preparation. The second operator was

trained in the scoring procedure, resulting in a

sufficient intra observer reproducibility.3

The apical, middle and coronal regions of the

canal surface, were graded (1-5) for debris and

smear layer, assessed and recorded. A statistical

analysis was performed using a Mann-Whitney

Rank Sum test. In addition, a comparison between

the scores of the Manual and Pro File groups for

smear layer and debris was made to determine

possible differences in the effectiveness of the two

techniques employed.

Discussion

Removal of vital and/or necrotic pulp tissue,

infected dentin, and dentin debris are the


ORIGINAL RESEARCH


Table 2: Mean Score of Debris at the Cervical Level among the Study Group

Experiment Mean ± SD ‘U’ Statistics Significance

M- Group 1.87 ± 0.64 84.00 p> 0.05

Table 3: Mean Score of Smear Layer at the Cervical Level among the Study Group.


M- Group 1.67 ± 0.62 110.00 p> 0.05

P- Group 1.67 ± 0.49

P- Group 2.20 ± 0.77

important objectives during root-canal

instrumentation. This procedure is important in

order to eliminate most of the microorganisms

from the root canal system.

The smear layer is a surface film of a thickness of

approximately 1-2 μ which remains on the root

canal wall after instrumentation.11 Smear layer is

absent on areas that are not instrumented. Smear

layer contains both organic and inorganic

components i.e. residual vital or necrotic pulp

tissue, dentin particles, protein agglomerates,

bacterial components, blood cells along with

retained irrigants, which blocks up the openings

of the dentinal tubuli. In this way, a thick and

non-homogeneous smear layer can prevent

effective removal of intracanal microorganisms,

and complete sealing of the root canal.12, 13

In this investigation, hand instrumentation was

performed with K-Flexofiles made of stainless

steel. These instruments utilize a triangular blank

as used for reamer with the flutes twisted more

tightly to give more cutting edges but

maintaining the same narrow cross-sectional

diameter for increased flexibility.14 They feature a

non-cutting tip15,16 and they were included in the

investigation because it was known on the basis

of earlier investigation that they are able to

enlarge, even severely curved canals with little or

no transportation.17 In a study of the machining

efficiency of various Ni-Ti and stainless steel files

reported that the most efficient of those examined

were Ni-Ti instruments and Flexofiles. They

attributed their findings to the increased

flexibility of these two instruments together with

their ‘aggressive’ cutting designs.18

Although it is recommended to use antibacterial

irrigants along with chelating agents in order to

remove debris and inorganic/organic smear

layer,3,12,19 in the present study EDTA was used as

an irrigant owing to its chelating properties on

inorganic component.7 But, it is not possible to

completely remove the smear layer with

EDTA.20,21,22,23 Recently, the paste type chelators

containing EDTA have regained popularity to be

used with Ni-Ti instruments, manufacturers

recommend their use as a lubricant during rotary

root canal preparation, to reduce the risk of

instrument separation.24 Nevertheless, the major

objective of the present investigation was to solely

compare the cleaning effectiveness of the two

instrumentation techniques under similar

conditions. To avoid any association of different

irrigation solutions, a simple irrigation technique

was used. Hence, it has to be considered that the

cleaning efficiency of the two instrumentation

techniques evaluated in the present study might

be further improved using a combination of

NaOCl and EDTA.


ORIGINAL RESEARCH


Table 4: Mean score of Debris at the Middle Level among the Study Group.


M- Group 2.20 ± 0.41 108.00 p> 0.05

P- Group 2.20 ± 0.77

Table 5: Mean Score of Smear Layer at the Middle Level among the Study Group


M- Group 2.40 ± 0.51 103.50 p> 0.05

P- Group 2.27 ± 0.70

Table 6: Mean Score of Debris at the Apical Level among the Study Group.


M- Group 2.93 ± 1.10 63.00 P< 0.05*

P- Group 3.67 ± 0.82

* Statistically significant

Table 7: Mean Score of Smear Layer at the Apical Level among the Study Group.


M- Group 3.07 ± 0.96 60.00 P< 0.05*

P- Group P- group

*Statistically significant

The SEM technique produces images of high

resolution and magnification. Apical, middle and

coronal sites for quantitative measurements were

chosen at random. On those occasions when

unprepared surfaces were found, a new site was

chosen for micrographic examination. The

magnification 200x was employed because it

offered a wider view and also a detailed image of

the surface. The micrographs at x1500

magnification might cover too small a surface,

give limited information and lead to a potential

misrepresentation of cleanliness.25 One weakness

of the evaluation of the micrograph was that the

measurements of debris and smear layer were

arbitrary and at best ordinal in nature. However,

there is currently no consensus in the

standardization of measurements of debris and

smear layer.26, 27

Apical extrusion of the material was observed

during the manual instrumentation, which is

consistent with earlier studies.28, 29, 30However this

problem was not evaluated, considering the low

frequency of exacerbation during clinical

endodontic work; this in vitro observation may

not be relevant in the clinical situations.

In the present study, the cleaning efficacy of two

instrumentation methods was examined by means

of an SEM evaluation of the coronal, middle and

the apical portions of the canals.3,4, 27,31,32,33,34 on the

basis of a separate numerical evaluation scheme

for debris and smear layer. Partially un-

instrumented areas with remaining debris were

found in all canal sections, with both

instrumentation techniques. This finding has


ORIGINAL RESEARCH


also been supported by other

authors.1,2,3,9,27,32,33,35,36,37

Using stainless steel K-Flexofiles resulted in no

significant differences in the amount of debris and

smear layer compared to the ProFile instruments

at the cervical and middle thirds of the canals

(Tables 2,3,4,5 Graphs 1,2,3,4 p>0.05).

Edgar Schafer et al. (2000) compared the efficacy

of manual and automated instruments. The

results indicated that stainless steel hand K-

Flexofiles performed better than ProFile rotary

Ni-Ti instruments.31

In a study by E.Schafer and R.Schlingemann

(2001) to check the efficacy of rotary Ni-Ti K3

instruments and stainless steel hand K-Flexofile,

the results indicated that Flexofiles allowed

significantly better removal of debris than K3

instruments.33

M.Ahlquist et al. (2001) checked the effectiveness

of stainless steel S-files and ProFile rotary Ni-Ti

files in cleaning of root canals and they found

stainless steel S-files produced cleaner root canal

walls.

The results of the evaluation of the apical third of

the specimens for debris and smear layer in this

study showed statistically significant differences

(p<0.05) between both the systems (Tables 6, 7

Graphs 5, 6). The manual group showed better

cleaning ability with respect to the remaining

debris and smear layer than ProFile group.

Similar results were obtained by M.Ahlquist et

al.(2001) when they compared stainless steel S-

files and ProFile rotary Ni-Ti files.27

The results of the present study indicate that on

an average the apical third of the canals was less

clean than the middle and coronal thirds

regardless of the instrument used. This

observation is also in agreement with other

studies. The results of E.Schafer and D.Lohmann

(2002) comparing rotary instrumentation and

stainless steel hand K-Flexofile showed that

completely cleaned root canals were not found

with any of the two instruments.32

In a SEM study of debris and smear layer

remaining following use of GT rotary instruments

by G.Gambarini and J.Laszkiewicz (2002), the

results showed that GT rotary instruments

removed debris effectively, but left root canal

walls covered with smear layer particularly in the

apical third.38

F.Heard and R.E.Walton (1997) in their SEM study

to compare four root canal preparation techniques

found the middle level was cleaner than the apical

or coronal levels.39

M.Hulsmann et al. (1997) compared the canal

cleanliness after the preparation with eight

different instrumentation techniques including

both engine driven and hand. They found best

cleaning ability achieved at the middle and

cervical thirds.3

The results of some investigations were not in

agreement with the above. M.F.Bertrand et

al.(1999) in the comparative study of removal of

smear layer using the Quantec Series 2000 and

stainless steel hand K-files found that Quantec

rotary system produced cleaner canal walls than

conventional manual instruments, particularly in

the middle and apical thirds.40

In the present study, overall performance of the

hand instrumentation was better than rotary Ni-Ti

despite the step-back technique used for hand

instrumentation group. The reason may be the

ability to clean effectively the endodontic space is

dependent on both instrumentation and

irrigation.38 The dentin filing using mechanical

endodontic devices is more extensive than manual

instrumentation and the amount of dentinal

shavings produced is, therefore, higher.21 It can be

concluded that obviously, even different rotary

Ni-Ti instruments vary in their debris removal

efficiency, possibly due to their flute design.19,40,41

ProFile instruments have U-shaped blades with

radial lands and it has been shown that this file


ORIGINAL RESEARCH


design was less efficient in debris removal. They

perform a planing action, compared to rotary

instruments having a positive rake angle which

could be the main reason for the inferior cleaning

ability.4,31

It was also observed that the cleaning ability was

inferior in the apical third of the canals when

compared to the middle and cervical third. The

reason for the incomplete removal may be an

irregular secondary dentin which is associated

with the physiological ageing of the Root42 so that

surface morphology, especially in the apical

region, is far from smooth, which is generally

advocated in endodontics to be typical of the

normal or well-debrided canal wall.35 The

incomplete removal of debris and smear layer in

the apical third may be due to the failure of

irrigants to reach the apical third.

During endodontic instrumentation of root

canals, products containing EDTA are used to

remove/reduce smear layer and debris, thereby

creating better access for disinfectants as well as

achieving a clean surface for the final seal of the

root canal. Two different instrumentation

techniques with EDTA as irrigant were used in

the study to assess the effective cleanliness. The

manual technique employed in the present study

produced cleaner root canal walls than ProFile

rotary technique. The subjective estimation was

that rotary instrumentation technique employed

was faster and was less tiring for the operator.

Summary and Conclusion

Summary

The aim of this study was to evaluate the

cleanliness of the root canal walls after

preparation with ProFile rotary Ni-Ti and hand

instruments.

ProFile rotary Ni-Ti instruments and K- Flexofiles

were utilized to prepare the canals with EDTA as

an irrigant. After the preparation of the canals the

specimens were split longitudinally and observed

under scanning electron microscope (SEM), to

quantitatively evaluate the amount of remaining

debris and smear layer using a numerical scoring

system.

The results of the present study confirm the

results of previous studies on rotary Ni-Ti

systems concerning the cleaning ability. Both

systems were ineffective in removing debris and

smear layer completely and K- Flexofiles were

better in removing the debris and smear layer

compared to ProFile rotary Ni-Ti instruments

especially in the apical third.

It can be concluded from this study that none of

the instrumentation techniques employed,

produced the canal walls which were free of

surface debris and smear layer. The manual

instrumentation technique was better in cleaning

the canals compared to the ProFile rotary Ni-Ti

instruments despite the step-back technique used

for manual instrumentation. Had a crown-down

technique been used for manual instrumentation,

it would have removed the debris more

effectively and produced better canal walls.

During endodontic instrumentation of root canals,

alternating irrigation with 5.25% NaOCl and 15%

EDTA should be used to remove/reduce smear

layer and debris, thereby creating better access for

disinfectants as well as achieving a clean surface

for the final seal of the root canal.

Even though the manual technique employed in

the present study produced cleaner root canal

walls than the ProFile rotary technique, the latter

method appeared to be less time consuming in

preparation of the root canal space and less tiring

for the operator.

Conclusion

K- Flexofiles were better in debris and smear

layer removal compared to ProFile rotary

Ni-Ti instruments.

No statistically significant differences were

observed in the cleaning ability of the two


ORIGINAL RESEARCH


instrumentation techniques at the cervical

and middle thirds of the canals.

Statistically significant differences were

observed with respect to the remaining

debris and smear layer at the apical level.

References

1. Bolanos OR, Jensen JR. Scanning Electron

Microscopic comparisons of the efficacy of

various methods of root canal preparation. J

Endod 1980;6:815-22.

2. Haikel Y, Allemann C. Effectiveness of four

methods for preparing root canals; a scanning

electron microscopic evaluation. J Endod;

1988;14(7):340-5.

3. Hulsmann M, Rummelin C, Schafers F. Root

canal cleanliness after preparation with

different endodontic handpieces and hand

instruments; a comparative scanning electron

microscopy investigation. J

Endod;1997;23(5):301-6.

4. J Versumer, M Hulsmann, F Schafers. A

comparative study of root canal preparation

using ProFile .04 and Lightspeed rotary Ni-Ti

instruments. Int Endod J; 2002;35(1):37-46.

5. Pashley DH, Michelich V, Kehl T. Dentin

permeability; effects of smear layer removal. J

Prosthet Dent; 1981;46(5):531-7.

6. Chirnside LM. The bacteriological status of

dentine around infected pulp canals. N Z

Dent J 1958;54:173-83.

7. Shovelton DS. The presence and distribution

of microorganisms within nonvital teeth. Br

Dent J 1964;117:101-7.

8. Mizrahi SJ, Tucker JW, Seltzer S. A scanning

electron microscopic study of the efficacy of

various endodontic instruments. J Endod;

1975;1(10):324-33.

9. Schwarze T, Geurtsen W. Comparative

qualitative scanning electron microscopic

study of automated vs. hand instrumentation

of root canals. Dtsch Zahnarztl Z 1996;51:227-

30.

10. Walton RE. Histologic evaluation of different

methods of enlarging the pulp canal space. J

Endod1976;2(10):304-11.

11. American Association of Endodontists.

Glossary Contemporary Terminology for

Endodontics, 6th Edition. American

Association of Endodontists, Chicago III, USA.

1998.

12. West JD, Roane JB, Goerig AC. Cleaning and

shaping the root canal system. In: Cohen S,

Burns RC, eds. Pathways of the Pulp. 6th ed.

Boston, MA, USA: Mosby Year Book, 1994.

179-218.

13. Petschelt A, Stumpf B, Roab W. Tightness of

root canal sealers with and without smear

layer. Dtsch Zahnarztl Z 1987;42:743-6.

14. Franklin SW. Intracanal treatment

procedures, Basic and advanced topics. In;

Franklin S. Weine, eds. Endodontic Therapy.

6th ed. Mosby, 2004. 208.

15. Larz Spanberg. Instruments, Materials and

Devices. In; Cohen S, Burns RC, eds. Pathways

of the pulp. 8th ed. St. Louis, Mosby, 2002.

530.

16. John I Ingle, Leif K Bakland, Donald L Peters,

L Stephen Buchnan, Thomas P Mullamy.

Endodontic Cavity Preparation. In; John I.

Ingle, Leif K. Bakland, eds. Endodontics IV ed.

Williams and Wilkins. 1994. 168.

17. Tepel J, Schafer J, Hoppe W. Properties of

endodontic hand instruments used in rotary

motion. Part 1. Cutting efficiency.J Endod;

1995;21(8):418-21.

18. Camps JJ, Pertot WJ. Machining efficiency of

Ni-Ti K-type files in a linear motion. Int

Endod J; 1995;28(6):279-84.

19. Gambarini G. Shaping and cleaning of root

canal system; a scanning electron microscopic

evaluation of a new instrumentation and


ORIGINAL RESEARCH


irrigation technique. J Endod; 1999;25(12):800-

3.

20. Sen BH, Wesselink PR, Turkun M. The smear

layer; a phenomenon in root canal therapy. Int

Endod J; 1995;28(3):141-8.

21. Liolios E, Economides N, Parissis-Messimeris

S, Boutsioukis A. The effectiveness of three

irrigating solutions on root canal cleaning

after hand and mechanical preparation. Int

Endod J; 1997;30(1):51-7.

22. O’Conell MS, Morgan LA, Beeler WJ,

Baumgartner JC. A comparative study of

smear layer removal using different salts of

EDTA. J Endod; 2000;26(12):739-43.

23. Baumgartner JC, Mader CL. A scanning

electron microscopic evaluation of four root

canal irrigation regimens. J

Endod1987;13(4):147-57.

24. Hulsmann M, Heckendoroff M, Lennon A.

Chelating agents in root canal treatment;

mode of action and indications for their use.

Int Endod J; 2003;36(12):810-30.

25. Mandel E, Machtou P, Friedman S. Scanning

electron microscopic observations of canal

cleanliness. J Endod; 1990;16(6):279-83.

26. Jeon IS, Spangberg LS, Yoon TC, Kazemi RB,

Kum KY. Smear layer production by three

rotary reamers with different cutting blade

designs in straight root canals; a scanning

microscopy study. Oral Surg Oral Med Oral

Pathol Oral Radiol, Endod;2003;96(5):601-7.

27. Ahlquist M, Henningsson O, Hultenby K,

Ohlin J. The effectiveness of manual and

rotary techniques in the cleaning of root

canals; a scanning electron microscopy study.

Int Endod J; 2001;34(7):533-7.

28. Martin H, Cunningham WT. The effect of

endosonic and hand manipulation on the

amount of root canal material extruded. Oral

Surg Oral Med Oral Pathol 1982;53(6):611-3.

29. Tucker DM, Wenckus CS, Bentkover SK.

Canal wall planing by engine-driven Ni-Ti

instruments, compared with stainless steel

hand instruments. J Endod; 1997;23(3):170-3.

30. Reddy SA, Hicks ML. Apical extrusion of

debris using two hand and two rotary

instrumentation techniques. J Endod;

1998;24(3):180-3.

31. Schafer E, Zapke K. A comparative scanning

electron microscopic investigation of the

efficacy of manual and automated

instrumentation of root canals. J Endod;

2000;26(11):660-4.

32. Schafer E, Lohmann D. Efficiency of rotary Ni-

Ti FlexMaster instruments compared with

stainless steel hand K-Flexofile-Part 2.

Cleaning effectiveness and instrumentation

results in severely curved root canals of

extracted teeth. Int Endod J 2002;35:514-21.

33. Schafer E, Schlingemann R. Efficiency of

rotary Ni-Ti K3 instruments compared with

stainless steel hand K-Flexofile. Part 2.

Cleaning effectiveness and shaping ability in

severely curved root canals of extracted teeth.

Int Endod J.2003;36:208-17.

34. Hulsmann M, Herbst U, Schafers F.

Comparative study of root-canal preparation

using Lightspeed and Quantec SC rotary Ni-Ti

instruments. Int Endod J; 2003;36:748-56

35. Bechelli C, Orlandini S Zecchi ,

Colafranceschi M. Scanning Electron

Microscopy study on the efficacy of root canal

wall debridement of hand versus Lightspeed

instrumentation. Int Endod J 1999;32:484-93.

36. Kochis KA, Walton RE, Lilly JP, Ricks L,

Rivera EM. A histologic comparison of hand

and Ni-Ti rotary instrumentation techniques. J

Endod 1998;24:286.

37. Park JW, Bh TS, Lee JY. Scanning electron

microscopic evaluation of the prepared root

canal surface by hand and rotary instruments.

J Endod 1998;24:293.

38. Gambarini G, Laszkiewicz J. A scanning

electron microscopy study of debris and smear


ORIGINAL RESEARCH


layer remaining following use of GT rotary

instruments. Int Endod J 2002;35:422-7.

39. Heard F, Walton RE. Scanning Electron

Microscopy study comparing four root canal

preparation techniques in small curved canals.

Int Endod J; 1997;30:323-31.

40. Bertrand MF, Pizzardini P, Muller M,

Medioni E, Rocca JP. The removal of smear

layer using the Quantec system. A study

using Scanning Electron Microscope. Int

Endod J 1999;32:217-24.

41. Hulsmann M, Versummer J, Schade M. A

comparative study of Lightspeed, ProFile .04,

Quantec and HERO 642. Int Endod J

2000;33:150.

42. Sen BH, Wesselink PR, Turkun M. The smear

layer; a phenomenon in root canal therapy. Int

Endod J; 1995;28:141-8.

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